Normally, Love Balls should apply a 8x catch multiplier if you are using a Pokémon of the same specie but of the opposite gender.
I have tried to catch multiple female Mawile by using Love Balls (while using a male Mawile, of course). However, it took me several balls each time, which shouldn't happen.

At full health, attempting to catch a Mawile with the condition specified above should render me with a 56.808% chance of catching one per ball. However, each time, the Mawile was under 40% of health left and often paralyzed. This ultimately should make the catch rate a whopping 100% per ball, even without paralysis.

I have tried to both start the battle with the male Mawile and by starting the battle with another Pokémon, and the issue remains in both cases. I have not yet tested this anomaly on another Pokémon. I used this website to calculate the catch rate: https://www.dragonflycave.com/calculators/gen-vi-vii-catch-rate

Love balls are currently applying the x8 bonus when catching pokémon of the same species and sex

Kind of hilarious if that's true; there was exactly the same bug in Pokémon Gold/Silver/Crystal.

Thanks for the report! It has been moved over to the Interal Tracker. Make sure to check back on the status of this Ticket.

Issue fixed, locking ticket